\documentclass{article}


%%-----------PGF/TIKZ
\usepackage{pgf}
\usepackage{tikz}
\usetikzlibrary{arrows,shapes,shapes.arrows,positioning}

\usepackage{palatino}

% Use preview.sty to crop the page
\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\setlength\PreviewBorder{0pt}

\begin{document}

\begin{figure}
\begin{tikzpicture}[node distance=10mm and 10mm,scale=.8]
    %at={\pgfpoint{0cm}{0cm}}
	\node(begin){\pgftext[left,at={\pgfpoint{0}{150}}]  {\includegraphics[scale=.4]{2.pdf}}};
    \node(subse){\pgftext[left,at={\pgfpoint{0}{75}}]   {\includegraphics[scale=.4]{4.pdf}}};
    \node(subtr){\pgftext[left,at={\pgfpoint{0}{5}}]    {\includegraphics[scale=.4]{6.pdf}}};
    \node(addtr){\pgftext[left,at={\pgfpoint{150}{150}}]{\includegraphics[scale=.4]{1.pdf}}};
    \node(addse){\pgftext[left,at={\pgfpoint{150}{75}}] {\includegraphics[scale=.4]{3.pdf}}};
    \node(end)  {\pgftext[left,at={\pgfpoint{150}{5}}]  {\includegraphics[scale=.4]{5.pdf}}};
    \node(phantom) at (14,8.5) {};

    
    \path[draw,double distance=1.2pt,-latex'] (3,5) to (3,4);
    \path[draw,double distance=1.2pt,-latex'] (3,2) to (3,1);
    \path[draw,double distance=.8pt,-latex'] (6,0.5) to [out=45,in=135] (7,0.5);
    \path[draw,double distance=1.2pt,-latex'] (10,4) to (10,5);
    \path[draw,double distance=1.2pt,-latex'] (10,1) to (10,2);

	
\end{tikzpicture}
\end{figure}
\end{document}
